13C-n.m.r. spectroscopic investigation of methylated and charged agarose oligosaccharides and polysaccharides

Lahaye, Marc; Yaphe, W.; Viet, Minh Tan Phan; Rochas, C.

doi:10.1016/0008-6215(89)84129-1

Cited by 162 publications

(59 citation statements)

References 34 publications

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“…2b). The large downfield shift of this signal was characteristic of methyl substitution (8-11 ppm, Usov 1984) and similar shifts have been reported in agars (Lahaye et al 1989, Lahaye andRochas 1991). The sharp signal at 59.0 ppm, which has also been observed in the 13 C-NMR spectra of some agars (Usov et al 1980), was assigned to the methyl carbon at C(O)6.…”

Section: C-nmr Spectroscopic Analysismentioning

confidence: 56%

“…The resonance at 92.1 ppm for the R. coccinea polysaccharide was further upfield than any reported Cl signal of AnGal for agars. Furthermore, the resonances of the polysaccharide from R. coccinea did not correspond to any of those assigned to agars bearing various substituents (Lahaye et al 1989, Lahaye andRochas 1991). In addition, it has been found (Liao et al 9 unpublished results) that the Brought to you by | University of Queensland -UQ Library Authenticated Download Date | 9/18/15 2:07 AM anomeric signals of a sulphated galactan with a nearly perfect disaccharide repeating unit of 6 f -Omethylated t-carrageenan occur at essentially the same positions as those of its unmethylated counterpart.…”

Section: C-nmr Spectroscopic Analysismentioning

confidence: 99%

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Cell Wall Polysaccharides from Australian Red Algae of the Family Solieriaceae (Gigartinales, Rhodophyta): Highly Methylated Carrageenans from the Genus Rhabdonia

Chiovitti¹,

Liao²,

Kraft³

et al. 1996

Botanica Marina

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The hot water-soluble polysaccharides from RJiabdonia coccinea and R. verticillata were characterised by a combination of constituent sugar analysis, sulphate and pyruvate content assays, infrared (IR) spectroscopy, linkage analysis, and 13 C-nuclear magnetic resonance (NMR) spectroscopy. These revealed unique polysaccharides belonging to the red algal galactan family. The polysaccharides had IR spectra resembling that of icarrageenan, but were rich in 6-0-methylgalactose (ca. 31 mol% and 17mol% for R. coccinea and R. verticillata, respectively). Data from 13 C-NMR spectroscopy provided evidence that the polysaccharides were carrageenans rather than agarocolloids. The preparations contained mainly ι-carrageenan, partially methylated at C(O)6 of the 3-linked galactose residue. The polysaccharide from R. verticillata also contained significant quantities of 3-0-methylgalactose and pyruvate. The unusual sugar 3-0-methylgalactose occurred primarily as main-chain 4-linked residues, with a small proportion in the form of terminal residues. Other structural variations occurred in the polysaccharides of both species. IntroductionThe phycocolloids from red algae are variously substituted galactans which form the dominant components of the matrix phase of algal cell walls (see Craigie 1990 for a review). The gelling and thickening properties and protein-reactivity of these phycocolloids have led to their widespread commercial use in industry (Glicksman 1987, Stanley 1990, Selby and Whistler 1993, Therkelsen 1993. The chemistry of red algal galactans has also been used to supplement classical criteria, such as morphology, anatomy, and life history studies, in the formulation of taxonomic hypotheses (e. g. Gabrielson and Garbary 1986, Doty 1989, Liao et al 1993, Chiovitti et al 1995.The galactans from red algae consist of repeating disaccharide units of alternating β-1,3-and a-1,4-linked galactopyranosyl residues. The disaccharide units are variously substituted with sulphate ester, methyl ether, pyruvate acetal, or single glycosyl side branches and the 4-linked galactose residue may be converted into 3,6-anhydrogalactose. There are two main classes of these galactans, the agars and the carrageenans. In ag rs, the 44inked residue is in the Lconfiguration, whereas in carrageenans, it is in the Dconfiguration. The 3-linked residue is in the D-configuration in both classes of galactan. Carrageenans are typically more sulphated than agars, and idealised carrageenan types (e. g. κ-, ι-, °1-) have traditionally been defined according to their sulphate substitution pattern and their 3,6-anhydrogalactose content. By contrast, agars typically contain significant amounts of methyl ether or pyruvate acetal substitution (Craigie 1990). The type and amount of substitution modify solution properties of red algal polysaccharides , Arnott et al 1974, Guiseley 1987.The Australian coastline is rich in both its abundance and diversity of red algae, but their phycocolloids have not been extensively studied. We are currently undertaking a progr...

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Section: C-nmr Spectroscopic Analysismentioning

confidence: 56%

Section: C-nmr Spectroscopic Analysismentioning

confidence: 99%

Cell Wall Polysaccharides from Australian Red Algae of the Family Solieriaceae (Gigartinales, Rhodophyta): Highly Methylated Carrageenans from the Genus Rhabdonia

Chiovitti¹,

Liao²,

Kraft³

et al. 1996

Botanica Marina

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“…Since agarotriose and agaropentaose can be produced in very small amounts only by /3-agarase I [29], the above results suggest that A. agarlyticus secretes both an a-agarase and a 8-galactosidase, the latter specific for the 3,6-anhydroa-L-galactose hydrate ends of the agaro-oligosaccharides. This is consistent with the fact that no activity, measured by a reducing-sugar method, can be detected in the culture of strain GJlB until a significant fraction of long agar chains is broken down (Fig.…”

Section: The Agarolytic System Of a Agarlyticusmentioning

confidence: 85%

“…It was not capable of degrading agarotetraose, agarohexaose, K--carrageenan, I-carrageenan or A-carrageenans. The agar extracted from the red alga Gracilaria eucheumoides, known to be partially methylated at C2 of the 3,6-anhydro-~-galactose residue and sulfated at C4 of the D-galactose residue [29], was not hydrolyzed by this a-agarase.…”

Section: Enzyme Specificitymentioning

confidence: 99%

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Purification and characterization of the α‐agarase from Alteromonas agarlyticus (Cataldi) comb. nov., strain GJ1B

Potin

Richard

Rochas

et al. 1993

European Journal of Biochemistry

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164

114

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The phenotypic features of strain GJlB, an unidentified marine bacterium that degrades agar [Young, K. S., Bhattacharjee, S. S. & Yaphe, W. (1978) Curbohydx Res. 66, 207-2121, were investigated and its agarolytic system was characterized using I3C-NMR spectroscopy to analyse the agarose degradation products. The bacterium was assigned to the genus Alteromonus and the new combination A. ugurlyzicus (Cataldi) is proposed. An a-agarase, i.e specific for the a(l+3) linkages present in agarose, was purified to homogeneity from the culture supernatant by affinity chromatography on cross-linked agarose (Sepharose CLdB) and by anion-exchange chromatograpy (Mono Q column). The major end product of agarose hydrolysis using the purified enzyme was agarotetraose. Using SDSPAGE, the purified a-agarase was detected as a single band with a molecular mass of 180 kDa. After the affinity-chromatography step, however, the native molecular mass was approximately 360 kDa, suggesting that the native enzyme is a dimer which is dissociated to active subunits by anion-exchange chromatography. The isolectric point was estimated to be 5.3. Enzyme activity was observed using agar as the substrate over the pH range 6.0-9.0 with a maximum value at pH 7.2 in Mops or Tris buffer. The enzyme was inactivated by prolonged treatment at a pH below 6.5, or by temperatures over 45 "C or by removing calcium. In addition, a 8-galactosidase specific for the end products of the a-agarase was present in the a-agarase affinity-chromatography fraction, probably as part of a complex with this enzyme. The degradation of agarose by this agarase complex yielded a mixture of oligosaccharides in the agarotetraose series and the agarotriose series, the latter consisting of oligosaccharides with an odd number of galactose residues.Enzymes capable of degrading agar polysaccharides have been isolated from bacteria [l-121 and marine molluscs [13]. These enzymes behave as glycosyl hydrolases, which hydroly se the P-D-( 1 +4) linkages between D-galactopyranose and 3,6 anhydro-L-galactopyranose residues in agarose and related polysaccharides, resulting in the release of neoagaro-oligosaccharides, with a D-galactose residue at the reducing end and 3, 6-anhydro-~-galactose at the non-reducing end [14-181.Another lytic mechanism, cleavage of the a-~-(1+3) linkages in agarose, was also reported [19-201, which yielded oligosaccharides of the agarobiose series, i.e. a 3,6-anhydro-L-galactose at the reducing end and a D-galactose residue at the non-reducing end. Agaro-oligosaccharides, however, have not yet been completely characterized by NMR. 13C-NMR spectra have been reported for unfractionated mixtures of agaro-oligosaccharides produced by a partially purified a-agarase from strain GJlB [17, 211. Only the anomeric carbons of the agarotetraose and agarohexaose aldito1 forms were assigned chemical shifts [20].As a prerequisite for the complete NMR characterization of the agaro-oligosaccharide series, we have further characterized the bacterial strain GJlB and purified its a-...

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Microwave‐Irradiated Synthesis of Agar‐Based Graft Copolymers

Mishra

Sen

Rani

2015

Surface Modification of Biopolymers

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13C-n.m.r. spectroscopic investigation of methylated and charged agarose oligosaccharides and polysaccharides

Cited by 162 publications

References 34 publications

Cell Wall Polysaccharides from Australian Red Algae of the Family Solieriaceae (Gigartinales, Rhodophyta): Highly Methylated Carrageenans from the Genus Rhabdonia

Cell Wall Polysaccharides from Australian Red Algae of the Family Solieriaceae (Gigartinales, Rhodophyta): Highly Methylated Carrageenans from the Genus Rhabdonia

Purification and characterization of the α‐agarase from Alteromonas agarlyticus (Cataldi) comb. nov., strain GJ1B

Microwave‐Irradiated Synthesis of Agar‐Based Graft Copolymers

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